hoffman



(No Model.) 3 Sheets-Sheet 1.

W. M. HOFFMAN.

LEATHER STAKING MACHINE.

No. 389,511. Patented Sept. 11, 1

3 Sheets-Sheet 2.

(No Model.)

W. M. HOFFMAN.

LEATHER STAKINGMAOHINE.

No. 389,511.- Patented'Sept. 11, 888.

In Van Z07.-

(No Model.) 3 Sheets-Sheet 3.

W. M. HOFFMAN.

LEATHER STAKING MACHINE.

No. 389,511. Patented Sept. 11, 1888.

Av an/07 .UNITED STATES PATENT OFFICE.

WILLIAM M. HOFFMAN, OF DETROIT, MICHIGAN, ASSIGNOR TO THE HOFF- MAN MACHINE COMPANY, OF SAME PLACE.

LEATHER-STAKING MACHINE.

SPECIFICATION forming part of Letters Patent No. 389,511, dated September 11, 1888.

Application filed January 24, 1888. Serialv No. 261,716. (No model.)

ening leather, hereinafter fully described and I3 claimed.

Figure l is a vertical longitudinal section on the line on m, Fig. 3. Fig. 2 is a side elevation, and Fig. 3 a rear elevation.

The principle of my invention consists in I5 staking the leather while one endis securely held by a movable stake-plate and a movable flexible pad for holding'the leather on the edge of the plate.

A represents the two front posts, and A the two rear posts, of the frame of the machine.

B represents two strong beams connected:

with posts A A and firmly secured thereto, preferably set on an incline rising toward the front of the machine.

2 B represents twosimilar beams, one end of each of which is secured to the-posts A, and said beams are supported on beams B by uprights a.

(1 represents bolts and nuts which tiethe 0 posts A and posts A together.

N represents two sprocket-wheels secured on the shaft G, which is journaled in bearings fastened to the beams B near the rear of the machine, and M represents two similar 5 sprock et-wheels secured to the shaft M, which is journaled in bearings secured to the beams B near the front of the machine.

I I representftwo endless chains, each of which connects one of the sprocketwheels M 0 and N.

O O 0 represent three boards, the ends of which are secured to the respective chains I, and which have angle-pieces c bolted to one of the links of the chains. On each board 0 5 is secured a stake-plate, P, shorter than the board and extending above the board and having its upper edge rounded, as shown in Fig. 3. The stake-plate P is preferably made of thin steel or other metal.

F and L represent sprocket-wheels, which said shafts being jonrnaled in bearings se cured to beams 'Bat the same distance apart as are the shafts M G, and these sprocket- Wheels are connected by an endless chain, J.

The sprocket-wheels F and L are adj ustably secured to their respective shafts, (the way shown in the drawings is by set-screws) so that the position of said sprocketwvheels and chain J may be altered without disturbing any other part of the machine.

Q Q Q. represent boardssecured to chain J, each having an angle-piece, b, which is riveted to' one of the. links of the chain, and these boards are placed at the same distance from each other on chain J that the boards 0 are from each other on chains I.

Z representsa pad of flexible material, such as rubber, secured to and projecting from each board Q, and the sprocket-wheels F and L are so placed on their shafts that the chain- J and boardsQ, with their flexible pads Z, lie substantially in a line drawn through the stake plate P at right angles to the chains I J.

D represcntsa pinion secured to a shaft, 0, to which motion is communicated by a beltpulley orany other suitable device.

H and K represent two gear-wheels of the same size secured, respectively, to the shafts G and E and meshing together, and the pinion D meshes in'to wheel K, so that when pinion D is rotated it drives the wheels K and H, and with them the sprocketwheel F and the two sprocketwheels N. with equal speed in opposite directions, and by means of chains J and I the sprocket-wheelL and the sprocketwheels M are also driven with equal speed in opposite directions.

Y represents a table extending across the front of the machine secured to the posts A.

T '1" represent the two arms of a bell-crank lever journaled on a shaft, U, secured to the front ends of the beams B, and the arm T extends down, either by itself or by an extension, V, far enough to'come in contact with the surface-table Y, thus forming with said table a clamp.

W represents a spring,which may be of any size or kind, connected with arm T of the bellcrank lever T T and tending to draw said arm toward the table Y.

R represents a tappet secured to the shaft ICO Lin such a manner that once in each rotation of said shaft it strikes arm 'I" of the bell-crank lever and forces the arm '1 away from the table Y against the resistance of spring IV.

S represents the leather to be stretched, which is held against the operation of the stake-plates by the clamp T or its extensionV and table Y.

I usually fill the space between the chains I with a canvas belt to support the leather. This belt may belaced to the chains and have slits through it to permit the stake-plates to rise above it.

The operation of my invention is as follows: The sprocket-wheels F and L are so adjusted that as they and sprocket-wheels M and N rotate the board Q, with its flexible pad Z, will travel through the space between the upper and lower sprocket-wheels slightly in advance of its corresponding board,O, and stakeplate P. This distance is adjusted with reference to the character ot'the leather to be staked, for it is obvious that the nearer the board Q and the stake plate P come together the stronger will be the grip on the leather ofthe flexible stretcher and stake-plate P. So for heavy leather these are made to travel closely together, and for lighter leather the distance is increased. The adjustment being madeand the machinery set in mot-ion, the operator, standing in front of the machinery, takes the leather which is to be staked, and as the clamp opens inserts it between the clamp and the table, where it is clamped and held. One of the flexible pads Z now comes in contact with the upper surl'ace of the leather, by which the pad is bent toward the table, and immediately thereafter the corresponding stake plate P comes in contact with the undersnrface ot' the leather, which is thus gripped flexibly between plate P and the pad Z, and as these move away from the clamp theleather is drawn over the stake-plate and is stretched.

Vhenever clamp T opens, which is once in each revolution of the sproeketwheels, as shown in the drawings, or may be arranged to occur more or less often, if desired, the operator moves the leather either from side to side or farther into the machine to stake each part of the leather until the whole has been stretched and staked, when he withdraws it from the machine as the clamp opens and puts in a fresh piece.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In a machine for staking leather, the combination, with a pair of sprockets carrying an endless chain having stake plates secured thereto at intervals,of a similar pair of sprockets carrying a similar chain provided with flexible pads secured thereto at such intervals as to co-operate with the stake-plates, and a suitable support for the leather, the chains being arranged to travel in unison and in suitable contiguity, substantially as described.

2. In a machine for staking leather, the combination, with a clamp for the leather having automaticintermittent action,ot'foursprocketwheels, two upon each shaft, carrying two endless chains, upon which are mounted at intervals a series of flexible pads, four similar sprockets similarly mounted and carrying two endless chains, upon which are secured a series of stakingplates at such intervals as to register with the flexible pads, and means for driving said chains in substantial unison, substan tially as described.

3. In a machine for stakin leather, the combination of the following elements: an interrnittingly working clamp for holding the leather, four sprocket wheels carrying two endless chains, upon which are secured at regu lar intervals a series ofstaking-plates, and two sprocket-wheels adj ustably secured to their respective shafts and carrying an endless chain, on which is secured at like regular intervals a series of flexible pads, the shaft of one ot'said sprockets having a tappet automatically releasing the clamp at each rotation, substantially as and for the purposes set forth.

4. In a machine for staking leather, the combination ol'the two sprocket-wheels M and two sprocket wheels N, connected by the two chains I, the stakeplates P, carried on said chains I, the sprocketwheels F and L, connected by chain J, and flexible pads Z, carried on said chain, the bell-crank lever T T, the spring W, the tappet R, and table Y, sub stantially as shown and described.

5. In astaking-machine. the combination, with a support for the leather, of two endless belts traveling in unison and in contiguity to eachother, one belt carrying at intervals a se ries of staking-plates and the other at like intervals a series of flexible pads, a bellcrank lever thrown by a spring into clamping engagement with the leather, and a rotating arm engaging the other arm of the bell crank at each revolution and releasing the leather, substantially as described.

WM. M. HOFFMAN.

\Vitnesses:

CYRUS E. LOTHROP, E. HESSELBASIIER. 

